Dissection - Technique

1/ Place the abdomen into a hot solution of potassium hydroxide. Warning! - KOH is highly caustic, boiling may cause it to leap from the tube and onto your skin or eye! The time taken to digest soft parts will depend on the solution temperature. Once ready, the abdomen will attain a translucent appearance and may tend to sink unless air bubbles prevent it from doing so. It is better to undercook than to overcook.

Tip: A 2 x 3/4 inch glass tube will hold enough solution to do many pugs or micros. Because of evaporation, top up with water every now and again

2/ Remove the abdomen from the KOH solution with either a hooked pin or a pippette and transfer to a dish or glass block containing purified water (not tap water!). Under the microscope, use small angled pins or a fine brush to remove as many scales as possible. Using pins, apply gentle pressure and stroking movements to the abdomen to push out the gunk. You should soon be able to see whether you have a female or male, and the proceedures for dealing with each differs.

Tip: Work towards slowly flattening the abdomen, but make sure it is flattened ventral side up or down, not laterally.

The figured example is a coleophorid. In the first image the abdomen is lying on its side and needs to be rolled over until itís lying on its back. In the second image, the abdomen has been gently flattened and some scales have been removed, allowing you to see some of the internal structure. An ovipositor has emerged from the left-hand side, so this is a female. (Itís often possible to identify the species at this stage.)



3/ Go to.....

Practice makes perfect - almost! Work on larger species first to gain experience. Donít be ambitious, dealing with tiny moths is an art - but things do become easier...

Dissection Index